Gardner Lindzey

Androgen Control of Territorial Marking in the Mongolian Gerbil

Gerbils mark objects with the secretion of a midventral sebaceous gland. Both the behavior and the gland integrity are under androgen control, as indicated by castration and replacement with testosterone propionate. The integrity of the gland seems less important for marking than an influence on the central nervous system, although the gland can be used as an external measure of androgen levels. It is possible that the secretion acts as a pheromone to signal territorial possession.

Spontaneous seizures in the Mongolian gerbil (Meriones unguiculatus)

Approximately 50% of the Mongolian gerbils in our colony were observed to display an epileptiform seizure when placed in a novel area. Forty-six percent of the susceptible animals were descended from two pairs of animals. Stimulus quality seemed to have little bearing on the response, but stimulus intensity was important. Daily exposure to novelty resulted in a progressive loss of seizure activity until no seizures were observed by the fifth day. The peak seizure time was at the height of diurnal behavioral activity. Dilantin, a common anticonvulsant drug used in human epilepsy completely eliminated the seizure as did reserpine. Brain histologies revealed nothing peculiar about the seizing animals. Neither dietary deficiencies nor infections seemed to be involved. The seizure pattern and the conditions under which it occurred suggest a variable genetic threshold response contingent on central nervous system excitation.

A scent marking response associated with the ventral sebaceous gland of the Mongolian gerbil (Meriones unguiculatus)

Abstract The Mongolian gerbil regularly marks objects in an open field by rubbing them with a midventral sebaceous scent gland. A method and apparatus useful for the study of this response are described. The marking and gland size are sexually dimorphic, with the male marking about twice as frequently as the female and possessing a gland roughly twice the size. Ventral marking in males is positively correlated with urination and defecation, and it is suggested that all three of these activities may in some situations be territorial scent marking responses.

Social interactions and scent marking in the Mongolian gerbil (Meriones unguiculatus)

Abstract Scent marking is common for many species, and affords olfactory cues for a variety of social reactions. The Mongolian gerbil ( Meriones unguiculatus ) marks objects with a ventral sebaceous scent gland. In both paired and triplet male encounters, animals marking most frequently generally become dominant. Grouping, however, can have the additional effect of depressing marking and morphological indices of androgen activity. In related studies it was demonstrated that males are attracted to the sebum coming from the scent glands of other males but not to sebum from females. Females show no obvious reference. These studies add support to the notion that gerbil marking has territorial significance and serves recognition functions.

The effects of olfactory deprivation and hormones on territorial marking in the male mongolian gerbil (Meriones unguiculatus)

Mongolian gerbils (Meriones unguiculatus) mark objects in their environment with a midventral sebaceous scent gland. In the male the response is androgen dependent. The first study shows that olfactory bulb aspiration almost completely eliminates marking behavior. The reduction is apparently independent of any hormone dysfunction, as indicated by weights of seminal vesicles, testes, and adrenals. Marking, however, can be at least partially reinstated with massive doses of testosterone propionate (640–1280 μg every 5 days), indicating a hormone compensation for a neurological defect and demonstrating that smell is not absolutely necessary for marking. The second study shows that 80 μg of estradiol benzoate but not 800 μg progesterone administered to males twice a week for 6 weeks significantly depresses marking frequency, causes atrophy of the testes and seminal vesicles, and stops spermatogenesis. It would appear that estrogen acts by antagonizing the secretion of gonadotropins. Animals were also assessed for preference or aversion of premarked pegs during this study, but no differential marking could be demonstrated. It is concluded that territorial marking is normally controlled by androgen and that the disruption of the response can occur either because of a lack of sensory input or an antagonism of the gonadotropic system.

Social dominance in the mouse

Two inbred strains of mice were opposed in measures of tube-dominance, food-dominance, and aggression, using matched pairs of individual opponents. There were stable strain differences on all three measures, and Ss within strains were highly similar to each other in performance. Results on the food-dominance and aggression measures were concordant, while performance on the tube-dominance test was negatively related to the other two measures.

Territorial marking in the female mongolian gerbil: Short-term reactions to hormones

Abstract Gerbils mark territories with a ventrally located sebaceous scent gland. For the male the response and gland morphology are strictly androgen dependent. In this study of the female, supplemental injections of testosterone elevated marking beyond that of either normal males or females and increased gland size. Estrogen, progesterone, and growth hormone were without effect. Regardless of hormone state there appeared a strong relation between marking, gland size, and gland secretion (gland blot).

Visual behavior of the Mongolian gerbil (Meriones unguiculatus)

The Mongolian gerbil, Meriones unguiculatus, appears to be deficient in depth perception. Whereas C57BL/6J mice show a predominance of shallow responses on a visual cliff (e.g., 100% of initial responses is to the shallow side), gerbils show random behavior (e.g., 56% of initial responses is to the shallow side). Gerbils are not blind, however, as they show a strong preference for darkness when allowed a choice, and their circadian activity cycle can be readily entrained with the light cycle.

Acrophobic and photophobic responses associated with the albino locus in mice

Albino and pigmented male and femaleF2 mice obtained from anAKR/J xDBA/2J cross were tested for acrophobic and photophobic behavior from platforms either 1 or 2.6 in. high and under red or white illumination. Latency to descend was greater for both genotypes from the high platform and also under red light. Albinos were especially hesitant, even when platform height was at a minimum and when testing was under red light. It was argued that albinism is not only associated with photophobia but with acrophobia as well.

Genetic aspects of negative geotaxis in mice.

Negative geotaxis in mice was studied at inclines of 20°, 30°, 40°, 50°, 60°, and 70° in five experiments. Experiment I describes a monotonic relation between orientation up the inclined plane and the angle of incline. It presents an efficient technique for studying this response and compares results with those obtained by earlier methods. Findings demonstrate that a random presentation of angles gives the same results as a sequential ascending presentation. Experiment II provides evidence for a steeper function relating incline with orientation for A/J than for C57BL/6J mice. F1 and F2 population results indicate dominance for the steep function, genetic segregation, and suggests the influence of the albino locus. Experiment III verifies the steeper function of the albino animals derived from an A/J and DBA2/J cross. Experiment IV depicts the operation of 14 single genes segregating on the C57BL/6J background. Three of the 14 genes, tortoise shell (To), buff (bf), and himalayan (ch), increase the steepness of the relation between orientation and incline angle. Finally, Experiment V illustrates a slight depression of orientation for the pallid (pa) gene which also disrupts the formation of otoliths in the inner ear.